A vehicle exhaust gas reduction system positioned in an exhaust system of an engine includes: an electrically heated catalyst (EHC) of heating exhaust gas of the engine by electrically generating heat; a sub-gasoline particulate filter (Sub GPF) heated by operation of the EHC to combust a particulate number (PN) included in the exhaust gas; a main gasoline particulate filter (Main GPF) of purifying the exhaust gas discharged from the engine; and a controller configured for performing PN reduction control by operating the EHC to be On in a low-temperature condition, and increasing a temperature of the Sub GPF to a reference temperature at which soot combustion is possible, combusting the PN passing through the Sub GPF and soot collected in the Sub GPF.

A mobile emissions control system is provided for diesel engines operated on ocean-going ships at-berth. The emissions control system comprises two essential elements: an emissions capturing system and an emissions control system. The emissions control system may be mounted on a towable chassis or mounted on a barge, allowing it to be placed alongside ocean-going ships at-berth. The emission capturing system captures exhaust from a ship's diesel engine and conducts it into the emissions control system, which cleans the exhaust and then passes clean air into the atmosphere through an exhaust outlet.

Disclosed power systems include an enclosure, an engine within the enclosure, a generator within the enclosure and configured to convert mechanical power from the engine to electrical power, an exhaust system, and one or more of, within the enclosure, welding-type conversion circuitry, an air compressor, a hydraulic pump, or auxiliary power conversion circuitry configured to convert the electrical power from the generator to at least one of AC output power or DC output power. The enclosure defines a rear surface when installed in a predetermined orientation. The exhaust system includes a muffler and a tail pipe, where an exhaust end of the tail pipe is at or near the rear surface of the enclosure.

Apparatuses and methods for tuning a muffler. An apparatus comprises a housing for a muffler, a first inlet pipe, and a second inlet pipe. The housing includes a coupling chamber. The first inlet pipe has a first set of physical features and carries exhaust to the coupling chamber. The second inlet pipe has a second set of physical features and carries the exhaust to the coupling chamber. The first set of physical features varies from the second set of physical features with respect to at least one physical feature such that a first sound waveform passing through the first inlet pipe and a second sound waveform passing through the second inlet pipe are uniquely tuned to thereby tune an overall sound waveform emitted by the muffler.

A pipe connection structure according to an embodiment of the present invention includes: two inlet pipes through which a gas is capable of flowing; a connection pipe to which respective outlet-side end portions of the two inlet pipes are connected at a distance; and an outlet pipe connected to the connection pipe at an opposite side to a side where the two inlet pipes are connected to the connection pipe, the outlet pipe being capable of being in communication with the two inlet pipes via a space section inside the connection pipe. The two inlet pipes include a first inlet pipe disposed on a first side and a second inlet pipe disposed on a second side, in a width direction of the connection pipe, across a middle of connection positions of the two inlet pipes to the connection pipe. The outlet pipe is connected to a position offset toward the second side in the width direction of the connection pipe. Along an axial direction of the first inlet pipe, the space section inside the connection pipe has an axial length not smaller than a virtual diameter D defined by following expression (1) D=(4A/), where A is a cross-sectional area of the first inlet pipe and is pi.

An engine exhaust device includes: a first catalyst; a second catalyst; and a tubular connecting member. The connecting member includes: a first opening; a second opening; and a bend connecting. A downstream end surface of the first catalyst is connected to the first opening, and an upstream end surface of the second catalyst is connected to the second opening. The downstream end surface and the upstream end surface form a dihedral angle within a range from 60 to 120 degrees. A part of the upstream end surface of the second catalyst includes an overlap that is close and opposed to a part of a surface of the first catalyst. The bend of the connecting member includes: a first wall; a second wall; and a connector. The first wall has a curve. The curvature radius of the first wall is greater than the predetermined curvature radius.

Briefly, in one aspect, a catalytic assembly described herein comprises a module comprising at least one layer of structural catalyst bodies having an inlet face for receiving a gas stream. A diffuser assembly is arranged a distance of greater than 50 mm from the inlet face, the diffuser assembly including at least one diffuser element comprising a plurality of apertures, wherein a ratio of aperture length (L) in the gas stream flow direction to aperture hydraulic diameter (D.sub.a) is less than 1.

An exhaust manifold comprises a plurality of exhaust intake conduits structured to be fluidly coupled to an engine and receive exhaust gas from a corresponding cylinder of the engine. At least one exhaust intake conduit provides a reduction in an exhaust intake conduit cross-sectional area from an inlet to an outlet. A plurality of bends are each defined by a respective one of the exhaust intake conduit outlets. An exhaust intake manifold is fluidly coupled to the exhaust intake manifold and defines an exhaust intake manifold flow axis. Each of the plurality of bends is shaped so as to define n angle of approach of exhaust gas flowing therethrough. A first angle of approach of the first bend relative to the exhaust intake manifold flow axis is smaller than a second angle of approach of an inner second bend.

A substrate for an exhaust gas treatment unit, particularly for an exhaust system of an internal combustion engine, includes a substrate body (18) elongated in the substrate longitudinal direction (S). The substrate body (18) is flattened in a flattening direction (A) essentially at right angles to the substrate longitudinal direction (S). A plurality of cells (24), which extend essentially in the substrate longitudinal direction (S) and provide flow ducts, are formed in the substrate body (18). The cells (24) are defined by cell walls (20, 22), which extend essentially in the substrate longitudinal direction (S). The cell walls (20, 22) are disposed at an angle in relation to the flattening direction (A).

An exhaust emission control device for an internal combustion engine according to the present disclosure includes an exhaust emission control catalyst provided in an exhaust passage in an internal combustion engine and divided into a preceding catalyst and a succeeding catalyst, and a heating device provided in the exhaust passage between the preceding catalyst and the succeeding catalyst. The exhaust emission control catalyst is divided into the preceding catalyst and the succeeding catalyst so that a ratio of a capacity of the preceding catalyst to a total displacement of the internal combustion engine is from 0.3 to 1.5.